Kibana Build details:

VERSION: 9.1.0 BC1
BUILD: 88126
COMMIT: 7f1cd025e139e0f76e4d67cadfa6c5cf9826d65f

Host OS: All

Preconditions:

1. Kibana 9.1.0 or above should be available.
2. At least one Agent Policy should be created.
3. At least one Agent should be installed.

Steps to reproduce:

1. Log in to Kibana.
2. Navigate to Fleet > Agent Policies.
3. Click on 'Manage' under Auto-upgrade agents for any policy.
4. In the 'Manage Auto Upgrade' flyout, locate the % of agents to upgrade input field.
5. Use the down arrow to decrease the value to 0.
6. Observe that the value can be set to 0, but an error message is displayed.

Expected Result
The minimum allowed value for % of agents to upgrade should be 1. The user should not be able to set the value to 0 using the arrows or manual input.

Screen Recording:

Feature:
https://github.com/elastic/ingest-dev/issues/2878